1. Fire Behaviour Chemistry of Combustion

2. Aim To provide students with information to give them an understanding of the behaviour of fire.

3. Learning Outcomes At the end of the session students will be able to: Describe the characteristic development and behaviour of a range of fires Describe the combustion process within a range of fires and the contribution made by different fuels to fire growth and development Recognize and interpret the characteristic development and behaviour of a compartment fire.

4. The fire triangle.

5. The triangle of combustion.

6. Conduction Convection Radiation. 3 methods of heat transfer

7. Heat transfer Metals conduct - some better than others, silver & copper are best Electrical insulators do not conduct heat well (plastics) Liquids and gases do not conduct heat well.

8. This shows how a fire may be spread in a building due to the conduction of heat along an unprotected steel girder.

9. Convection Only occurs in liquids and gases Central heating systems Chimney stacks Shafts in buildings In fire situations in a room -mushrooming.

10. Convection in heated water.

11. Central heating system using convection.

12. Convection causes the updraft in chimneys.

13. This shows how fire can spread by convection.

14. Radiation Heat is transmitted by infra-red radiation Travels in straight lines Casts shadows Will transmit through some materials and not others Absorption Reflection.

15. The inverse square law as applied to radiation Double the distance - quarter the radiation.

16. How fire can start from radiated heat.

17. Chemistry of combustion Atom - smallest particle Molecule - atoms chemically bound together Elements - contain one sort of atom Compounds - formed from one type of molecule which contains more than one kind of atom Mixtures - contain more than one kind of molecule.

18. Combustion Flashpoint Firepoint Fireball Spontaneous ignition temperature Spontaneous combustion Smouldering.

19. Development of compartment fire Fire starts Gases rise - form plume Convection takes place - mushrooming Plume radiates heat outwards Other fuels start to generate flammable gases Conditions ripe for flashover.

20. The fire plume.

21. Smoke layer at top of room.

22. Products of combustion Heat Smoke Light Gases that are toxic/noxious/irritant Carbon monoxide Carbon dioxide Water vapour.

23. Safety Wear full firefighting kit (inc. gloves) Wear BA with balaclava Use recognised BA procedures Limit exposure to high levels of heat and humidity.

24. Confirmation Assessments will be based on this lesson and the corresponding study note Learning Outcomes Describe the characteristic development and behaviour of a range of fires Describe the combustion process within a range of fires and the contribution made by different fuels to fire growth and development Recognise and interpret the characteristic development and behaviour of a compartment fire.

25. THE END